That was a good question. I had thought about that issue but never got round to asking. The reason being was that I was going to introduce a couple of family members to CC but they would be using the same PC and I was afraid that I would look like a multi !
Both joined same day though....17.43 and 18.26 on 4 June. Neither appear to be novices though. I suppose they could have just spontaneously just decided to work together but the game play was suspicious.